As the keynote speaker at Wanaka's 12th annual New Zealand Mountain Film Festival and one of the world's leading female ice climbers, Ms Calhoun is spreading a message of ''voluntary simplicity'' to address the impact global warming is having on alpine ascents.
''We don't need to fill our lives with stuff which doesn't get us where we want to go, which for me happened to be upwards,'' she told the audience at the Lake Wanaka Centre on Saturday evening in the first of her two talks during the festival.
Self-described as a minimalist focused on ''micro goals, not micro possessions'', Calhoun, now living in Utah, once spent months living in her car and surviving on just $14 a week for food.
Titled ''Last Ascents'', her talk is inspired by routes which may never be climbed again as global warming has caused snow and ice to become unstable, rockfall and recession of glaciers, meaning pilots can no longer land.
''I started recognising it in 2005 ... I just can't ignore it anymore,'' she said told the Otago Daily Times.
Her talk covers three different expeditions. In one, she was stranded in a storm for five days without food.
Weak with hunger and exhaustion, she and her climbing partner were forced to shed much of their equipment to survive their descent.
''The last one pointed me towards a new approach to climate change and that's a life of minimalism where we don't take everything or use it up or spend it, so that there's something left to leave behind for future generations.''
Calhoun, who said she was ''old enough to know better'' when asked her age, started rock climbing at age 18 in South Carolina, after a boyfriend broke up with her and she ''sought refuge in the mountains''.
She later took up mountain and ice climbing, the latter of which she considers the most visually rewarding.
''You have these [ice] formations that are chandeliers, kind of candlestick-like, and mushrooms. And it's extraordinary. It's really beautiful. There's different shades of blue.''
The ''dramatic'' scenery flying over the mountain ranges into Queenstown last week on her first visit to New Zealand also struck her as ''absolutely beautiful'' and has her considering an extension of her stay in the country.
Having climbed throughout the world, part of the lure of coming to New Zealand was another new climbing experience, something festival director Mark Sedon had promised to deliver, possibly on the Remarkables mountain range.
Ms Calhoun will give her final talk in Queenstown at 7.30pm Thursday at the Memorial Hall.
The festival continues in Wanaka today with a youth programme featuring films and a talk on mountain guiding by Mr Sedon, a ski and snowboard-tuning workshop and a snow sports film session this evening.
